Party-line telephone



T. G. MARTIN. PARTY LINE TELEPHONE SYSTEM.

APPLICATION FILED IuLY 5. i910.

3 SHEETS-SHEET l.

Patented Nov. 1l, 1919.

T. G1 MARTIN.

PARTY UNE TELEPHONE SYSTEM.

APPLICATION FILED JULY 5.1910.

Piiiene Nov. l1, 19123.

3 SHEETS-SHEET 2.

TI G. MARTIN.

PARTY LINE TELEPHONE SYSTEM.,

l APPLICATION FILED .IULY 5,1910. 1 ,$321,319. Patented Nov. Il, 12H9.

3 SHEETS-SHEET 3.

lHlilIllllllllI WYTNESSES one subscriber ou party-line to' cal'l an- TA'LBO'I G. MARTIN, O F OIIIcAGoI-LLINOIS. AssIGnoR TOAUTOMATII'LECTIC l.colera nya-OEMQHICAGO, ILLINOIS, `A'CORPORATION OI;` ILLINOIS.

PARTY-LINE TELnPIIoNEsysTEi/I.. f i

Be it known that-1 'l`.\i,i'.w'r (l`.'.\"l.\ii'i`i.\',a I' citizen of the United States-of Aiiiei'icafaiid resident of Chicago, (`ook county. llllliO-lh, have. invented a cert-aiu new and' useful Iii-i- ]iioveiiieiit -iii lartyliine 'leleplione Syst tems, of whicli'tlie following' isa-specification.

in which iii'eai'is'are. pi'o\'i.ded.ior enabling other subscriber -on tli'e'f saine line.' Iii 'aii." autoiiiatie systenrthis. hasheretofore been vjfdone "by" a connector which isjadapted -to' connect iizitlitlie. calli iigY line. or by 'aspecial equippediw-itli a. ringing cou'nectionfor pros' thi-is enabling one subsribeito automatidoes'iiot pass" through a connector, lintl sinilily goes to tlieaiitoiiiatic ringing-apparatuswhich sends signaling' current l'iack-oii'to'tlie calling line, wl'ii' cl`i is also,"of course, the

called line. These. .ai-raiigeiuents, however,

i are not altogether satisfactory.

My iiivei'ition contemplates, therefore, a system in which one party calls another o iI- tlie saine-line by connectingA witlil a'maniial 'lioard which is equipped with a selectiveiingiug keybv-wliicli the, called party on-.tlie

saine line is' sigiialei'lfafteitheoperator ali- In air autoiiiatic systeiiiiii which one party..

callsl fanotlier (Sii-" 'tliesaii'ier line throiiglia more'. simple and"tlie' i'esiiltsl are more satis.- Vfactory,

' `jTo these 'aiidfotlie`r usefull ends my inventioii consists in mattershereinafter set-forth' aiidgclaiined.-

obtain connectionwith af ealled'lii'ie in Fig.-

i lsaiiie'line as the' call-ing siil'iscribei", in a sys;

lem embodying the principles of my in ven tion.'v

1" 'ig. 3 is a '(liagrainmatie re resentatioii of a' poiition of the central o ce .appa',ia .t us

Spebication of Letters Patenti' nppiici'inicq nays, 1910. serial No. 570,465.

fai-exited Non' 11,1919. A

illiistfi'atiingr the. principal, tentures of the socalleijljiiiasterswitch E (Fig. 1).:l flfig. lj'sliows diagrainiuatically two pa'rt\- line s'iibsitatioiis A 'and A conneetecl over. lme'coiidiictors. to' the individual or lineA 60 switch which in turn has access to therst selector l). :'.ll'ie line switch C isv one of a groupof line switches Kwhich isjcontr'olled by- My invention -i'tlatesfto telephone systeins a..com`nioii..niechanisiii E'iisually called a.' master .-':\\iteh` ,A This in'astei'lswitch controls 65.

the pjliingers'of the group oflin switches in .siicli a ii'i'aiiiier that they are normally he'ldV opposite the 'terminal-of. anime-trunk line .lea'iliiiirfto 'a selectori); Tlie contacts of somei certain level of' the banks. of the 'selector .D 70

are' connected to tri'ink' -lines AF' \vhic'h leadI to a-iijoperatos position on a nianual "board. The remaining contacts -of-the 'banks of the selector )-forin terminals of trunk linesV leading t'o second'selecboisfH. Thefselectorw H liasaccess through its'banks .to .trunk lines.

Fig". 2) "are similar t`o the line sWitch'C'and- 80.

si'ibstation A shown inFig. 1. At B is showna battery for Vtalking and operating purposes',

.lia-ring. its positive-terininal preferably grounded atG. -Tlie1e may', however, be any number of batteries',` depending'on the con- 85.. ditions to begiliiet, Atla ringingfeurrent. generator is shown Vand a t`M a busy signal-A ing machine 'is represented; f It a partyline siibsc 1be'r, the subscriber at substation A, Afor example, desires to call' 90 a substation on seine line other than hisown, substation A2, for' example', he operates his ea-llingideyice--for the'digitsof the desired.

ni'inibe'r, wherebyfaconnection is setup tli'rougli the lane` switch (llselectors' D and 95 H and connector. I.' to, the called substation. i

If, however, the subscriber at substation desires to call another subscriber on his own 'line'lhe calls 'the 'digit-1corresponding to the .ban-k level of :the selector D', l(he contacts' of .100

*wh-ich leadto the operatorstrunks F, .The operator tl'iei'eupon presses suitable' key `to project riiigiiigir current' 'back upon the-,called lineto .signal the desiredsubstation.v 'The automatic substations niaybe'of any 105A siii'table'orapproved type; .Asherein repre? sented, the siibstationfA eo'iiiprisesthe usual receiver 2, switch hook 3, transmitter 4, .'bells', condenser 3, and, fbeing an automatic substation, it. has the iii'pulsesprings? and 110 S whichv are forced out of engagement by the teeth 9 on the impulse wheel 10 upon the backward rotation of said impulse wheel. The impulse wheel 10 is secured to shaft 11 to which there isv also secured a dial (not own) provided with finger holes. Allotted to the main line conductors 12 and 13, which are common to the substations A, A', etc., there is the line `switch C.

The line switch C is of the same general type as disclosed in British Patent #26,301 ot 1906. and also disclosed in the America-n TcZc//zoae Jour/:a1 of June 6, 1908, being of a somewhat modified construction, however. The switch consists essentially of the magnet ll which controls the usualplunger arm 15, on the end ot which is a plunger 39 (Fig. 3). The magnet 14 comprises four'windings, namely. pull-in' winding i6, cut-oil winding 1.7, line winding 18'and auxiliary winding'19. The magnetic circuit of the' windings 16 and 17 is separate from that of windings 18 and 19. 4This is due to the shape ot' the core. Asshown, the core has a flange or projection near its center to which the bracket 20*l is secured, the armatures being mounted upon the said bracket. Thus the windings 18 and 19' attract the4 armature 20, and windings 16 and 17 attract only armature 21 and plunger 'arm 15. The winding 16, when energized, is 'of sufficient strength to pull up both the armature 21 and plunger arm 15,\while the winding 17 .is only of sufiicient strength to pull up the .A ,armature 21, but will hold the plunger arm 15 in an operated position after it has been pulled up by the winding 16. Vhen the plunger arm 1'5 is attracted the plunger 39 (Fig. 3) is forced into a bank of springs and forces/the springs 22, '23, 24 and 25 into engagement with the springs 26,- 27, 28 and 25), respectively. There'is only one set of these springs (Q2-29) shown, but-there may be. a number of suc-h sets in the bank to which the plunger of the line switch C. has access, each set containing terminals of trunk lines leading to selectors similar to thc selector D, and each'v set is connected in multiple with the corresponding sets in the banks of all the other line switches of' the group ci which the switch C is a` member.

'l'he master switch 'E (Fig. 3)' is of the same general type as is disclosed in the British patent hereinabove referred to. and more particularly that shown in said/intericrm Y'cc/f/un/c Journal of June (3,1908, but,

like the line switch, is modified in 'construction. lt comprises the ratchet Vwheel 30, motor magnet 31 for operating said wheel, relays 32 and 33. andthe locking plate 34 near the outcr edge ofwhich are openings 35, whiclropcnings may be engaged bythe pin 3G on the arin 317. The plate 31 is secured to the shaft (Fig. 3)4 which is connected with the plunger shaft 38, with which the plungers are normally in engagement. The

openings in the locking plate til can be engaged by the pin 256 only when the said plungers 39 are directly opposite the terminals of. .a trunk line leading to a selector D. The Unister switch also comprises a bank a consistingof'individual segments o and a common segment l0. Sonie one ot the individual segments o (there being one t'or each trunk line leading to selector E) is kept in electrical connection with the couunon segment l() by ineans ot' the wiper l1. The rotary motion of thc ratchet wheel il() is transmitted to the plunger shaft 38 by means ot' lilik 30 and shaft 38. thereby giving said plunger shaft an oscillatory motion to carryr the plungcrs back and forth in front ot' the trunk terminals.

The selector switch D is ot' the general slightly modified to operate in conjunctionV with a two-wiresystem. It comprises the usual shaft (not shown)'carrying the wipers 42, 4,3 and H. This shaft has a vertical'mo-v tion controlled by the vertical magnet 45 and a rotary motion controlled by the rotary magnet 46. The selector is also provided with the slow acting relays 47. 48 and 4S) (by slow acting" I mean relays that are slow to denergize after their cncrgining circuits are broken). double-wound relay 50, release magnet 51 which isfSupplied with battery current only when thefsliat't is raistfd one or more steps, tlnirelry lifting the arm and permitting spr ng 53 to engage spring 54, and private magnet The private magnet 55 controls the usual sidi` switch carrying the` wipers 51', 5T. 58' and 5). i V 'The' trunks l" leading to4 thc opcrators position are each supplied with a doublewound relay (il), lamps/til and (i2. relay 68, master kcy K and ringing keys K. K2., K3, ctc. By means ot' thc kcys K', KL', K, ctc.. ringing current oflditi'crcnt frequencies,may be connected with the trunk linc.

The, operatofs talking sot is shown at S.

The. selector ll, Fig: 1. is similar to the selectorD.

The connector l, Fig'. L). is ot' the general type disclosed in United Stal's licttcrs llat-4 ent #815,176, granted March 13, lfltll. to Keith, Erickson and llrickson, boing modified, however, to opcratc in a two-wire system. The connector, like the selectors. is provided with a. doul'ile-wound relay 64, yertical magnet 65 and rotary magnet G6 `tor controlling the wipers (3T, (58 and (if), a release magnet 70, slow relays 7l and 72, and private magnet 73 which controls the side switch wipers 74, 75, To. 77 and 141. ln addition, the connector is supplied with a ringing relay 78, back-bridge relay 79 through which the called subscriber receives talking hutteryfeuirent, :indu husy locking .relay 80. The line'switcli-C und substation Arlenrer'undei'stniuling .ofrinfyin ventioii Y unify-be hizul hy considering.fits. opl-minions when one subsrrilier cnlls niiqihlri.' First 'I ill explfiiii liofw the siih'scrillxfiriit'slihsl'ut ion I nezthufis, when .suhsrribeirfut Aslibstn'tioi. ,it substation Atfor nf-itliJtlie spring 81,.. 'whereby'."ii circuit 4conip'letedf through; the pull-in .winding 16 iii series with the' auxiliaryV \\'"in( 1ing'18. This' Y- circuit exteiulsfrorirgrouml-G througlillic springs 81' und 5)() 'mul .windings- 16 :nul 18 tothe battery 'lezulj89. !.The-pul-l-in winding 11i. upon enf-rgiziiigrputtriiets both llie-ui'inu' tui-e111 u nglhe plunger urni 15. The :irn'u'iground' (l-through the lower winding fr ffi''f lay' 50, side switch Wiper 5.6,jlienkspiiing'ifs-29'1 z lineu'imling 19 hy sepurutngihe .springs und H13 from the spriiigs'Sl 'niul. 87, respecs tively, zi'inl :ilso'rhy shifting the spi-ing 86' into engagement u'itlis pringj88'rloscs the Howe-rer, isfui'irtion'less :it this time. The pulling'up ofilieplunger urni '15 operates :is befoi'estnteil to elosetli'e springs .22.123, .24'

:inkl into engz'igenieii't )ritlr'spriiigs 2li, Eiland The closi'iruof springs 22 und 2.5. ivil'h's'prings sind 29,' respectirelyycloses. 'the circuit ofthe dolililefwoiind lin'e'ifelii-y 5U of the selector. D. -flhisucireuit eigeiulsfroni" .tion A. :isl'irevionely traced, buckwverfline *winding'oimeliiy .toliattei'y'I .The relay` 50 energizes over` Athis circuiffto close u c ircuit through Vthe slow ieluy 49 extendingroni. ground l -'through spr'iii'gs' 93 und; 94

und slo\\"relu'y 49 lo buttery." ,The reley upon energizing, 'sliiftsspring '95 ont Q'fenguge'inent with "spring 9.62 and into enggige-L nient with' sp'ring'fl', und a1so-foi-'ces spring 98ir'ito engagement; with spring 99.' The closing of springs US unrl- -99 closes u circuit'.

a.. 1 tl'irongh the winding 14 of the lrnes-'ilrn lzinrl :i'lso extends :igual-(ling potentiail over con(luder-195'to'the -priri'ite bunk contnrt ol' thee;illiii'g"liiie in 'the bunks of :lll of the connectors thntliuve ucress to s :iid line. .'llie circuit through the iinrliiig'lextends-from ground .through springs Q8" umh- 99,

ilu-nre over conductor 100; through.springs und .lund- "indingl'to h utteilv;l This ci'ifuuitisclosed through the winding 17 liefore the' :irinutnre-:ZO lm's'lliuil 'tiine to full bark upoii t l ie bieukingjof the' circuits of `the winding "1U 'ut the .springs .81 :unl-'STL "I`he.aii-'iii:i.tui'e 20 is'l'ield iniin'- operated-p0- sitioii for :i moi-nent after the" Circuit-oli the When-A ie.plunger iii-ni reaches its loperated position. tlieeivinding 18 is sliort-cii'cuited, thereby causing 1t to denergif/e slowly' und :winding 17,. iispre'viou'sl traced, This env er'iergiziiig circuit through-thereby off 'the-muster s\viteli.. Assun'iing that tlie trunk picked l-i'y the; plunger was tliefirstLj trunk, the innstei' switch' wiper willg'be en the. contact 103; hence the circuit through the relu y zjnextends .frin'ground GrA through the springs 21 und 28, Contact .103, 'wipei' '41,

.connnon segment 1.0. und relay 32 tob'nttei'y,

Thei'eluy- A32, upon energizing, closes' 'the pulling up', liftsthe pin 36 Troni-.the opening 35 iii 'theplziteih disconnectsbattery' froin'l the pullfin windings of: the remainingidlel line 4`switeliesof the group Lo f wiiicl'1 the! switchfC'is a member di'scnnecting'the closingthe springs-104 and lof'zonnecls the at this relation between'tghezwindings-.an 19 'o'f. '-1'2-0- motor in ugnet Thiscireut extend-Sironi ground GY.' through `tl ie .molloif .magnet -3'1,

nterrupter sp-rings; ,106, contact-'.107' a'jicl .armature 37 to: battery-J The, -interrupter Whee1.`30, and obnsequentlyfw vnove '.lle; plungersv from infront of the As soon is thel shaft is moved a short distance the hole. in the plate 34 which was engaged by the pin liti passes from under the pin. 'l`he pin 16 then rides on the'plate 34 and continues to hold the cil-'cuit of the magnet 2t closed at'ter the wiper 41 passes ofi' the contact 1025 and until the pin liti engages the, next opening, at which time the [,)lungers will. as hereinlwt'ore stated. be directly opposite the terminals ot' the next trunk. l\`hould the next trunk be busy the relay 32, which deiinergized as soon as the wiper 41 passed ott` the contact. 103, will again be energized and the pin 36 will not be permitted to engage the next opening. and consequently the plungers will be moved to the next' trunk, and so on until the wiper 41 strikes a nongroundcd contact.

The foregoing operations take place upon the removal oil the receiver at the calling substation, rl`he subscriber at substation A now operates the calling device for the firstdigit 2. The circuit ot' the relay 50 is broken twice at the impulse springs 7 and 8. rl`he relay 3() momentarily deenergizes twice, and completes-a circuit through the vertical magnet 45. 'l`he relay 49 being slow acting doesl not deiinergize during the momentary interruption ot' its circuit at springs 93 andV 94: therefore the circuit through the vertical magnet 45 extends trom ground (1 through springs 93 and U2. springs 95 and 97. slow relay 48. vertical magnet 45 and lside switch wiper 59 to battery lead Sil. 'Ihe vertical magnet energizes twice to raise the shaft and shaft, wiuers two steps to a point opposite the second level ot' bank contacts which are terminals ot' trunks lead-ing to the selector' ll. The relay-4S` which is energized as soon as the rst impulse is sent through it, being slow. remains in an energized position until a moment a'l'ter the last impulse. is delivered.

-In its energized position it closes the circuit ot the private magnet 55. This circuit eX-l tends t'roni ground (i through springs 108 and 169 and private magnet- 55 to battery. The relay 4h'. upon deenergizing` breaks the circuit just tracedl andallows the privateAJ magnet to d'eenergize` which in turn allows the side. switch to pass to Second position in the usual manner. The p'assing ot the wiper lto second position shifts the battery connection from the vertical magnet 45 to the rotary magnet 46. A circuit is then completed through the rotarymagnet extending from ground G2 throngh'thc interrupter springs 110, rotary magnet 46, relay 47 and side-switch wiper `59 to battery. The rotary magnet operates to rotate the shaft wipers one step onto the contacts ofl .the first `trunk line leading to aselector H,

and also presses down the private magnetarmatureJ and breaks its own circuit at the interrupter springs 110. Upon breaking its own circuit it allows its armature to fall back. and if the first trunk is idle the private magnet armature will also t'all back and allow the side switch to pass to third position. It', however, the rst trunk is busy the private magnet armature will be held u'p hy 70 a circuit through the private magnet, said circuit extendingt'rom ground G7 through the selector H Elonging to the busy trunk to the first priva l bank contact in the second level ot' the selector D, tl" nce through the 75 private wiper 43, side switch wiper 58 (in second position) and private magnet 55 to battery. The private magnet. thus locks tl i side switch in second position and the rotar magnet is again energized to rotate the sha t wipers onto the second contact. These operations are repeated until the private wiper strikes a non-grounded contact, at which time the side switch passes to the third position. The passing of the wipers 56 and 57 85 to the -third position completes a circuit through the 'double-wound relay 111 of the second selector in the same manner as the circuit was completedthrough the relay 50 of the selector D. The relay 111 pulls up 90 and closes a circuit through the relay 115. :flic relay 115, upon energizing, puts a holdmg circuit back over the release trunk 119 to the relay 49 ofthe selector D, and also puts a guarding ground on the private banks of all the tirst selectors that 'have access to the selector 'lh This guarding ground eX- tends from ground (l7 through the side switch wiper 116, springs l1`7 and 118 and conductor 119 to the said private contacts. 100 The circuit through the slow relay 49 eX- tends from this ground at the private bank contact through the private' wlper 13,` side switch wiper 56, springs 12() and 121 and relly 4U to battery. Thus the relay 49 re.- 105 (mains energized after the relay 50 has deenergized. A short period of time elapses between the time that the wipers of the selector D pass to third position and the time, that the relay pulls up to place a 110 guarding ground back, as explained, during which time ground is supplied to the private bank contact from gronndt (la. It will be rememberat'l that the relay 17 was in the circuit with the rotary magnet and was ener- 115 gized by the first impulse, but beincr slow doesnot deenergize until a moment a ter the side switch has passed to third position;

therefore a circuit extends from ground G8' through springs -122 and 120, wiper 58 to 120 private wiper 43, thence' to the private ha nk contacts above mentioned. The, relay 47 must be quicker than the. relay 4 9, however,

in order to permit the springs and 121v to close the circuit of relay 49 before it de- 125 energizes.

The subscriber atsubstation A now operates the `calling device for the second digit 2: The operations of the selector H are the same as were those of th selector D, 189

Briev. the .oi'ierations of the selector .H are;

V line. The relay 'Ileupou energizing. closes.v

as follows: VThe ei-i'llingdevice opens'tlieli'ne twice. therebybreaking th'eYirciiit ot the relay'- 111 vtwice. The relay .111 d energ'i'lfes to twice close the 4circuit through .the relay 11:2 and jvertical inacfnetlll. These o )erv ate, as described,'for thef'selector D to raise theshaft andshaft wipers' two steps, and to also energize. and@denergize the: private 'magnet 11.4.v which in tii'in pernits the-side Switch to pass to second position.;lVlien the.

side switch is in second' ositi in the rotary inagnet operates to rotatil the shaft-onto 'an 'idle trunk line leading to 'a connector I, and the private magnet again ope'rat'es'to permitthe side switch to passt-tithe 'tliiiftl'po'sitioin whereby acireuit'is closeil 'tl1i 'oiigli the re tends from ground G through linveijnvjintlf vside switclrwiper 125. 'conductor 1.2

44 (which would be standing-fon=1contaet{ 1:27); thence over the heavy conductor to and .through substation A. liacl--ovethe-heavy ing of relay (54, condactor-. 123,. 'i\'iper 124, viper i duetor 129. wiper 130, shaft wiper 131, con' to battery. The relayftifjenergizes'to close' the eii'cuit'of the relayintheSanne-inarr-4 ductor 132 andyupperl winili-n'gof. relay 6 4 ner as the circuits were 1closed'tlrrouglrthb relays 1'15 "and 4 9 ofgthe seleetors, The relay 72, upon energizing, performstlie same functions as did relay' 11a-that istvputs guarding and holding` ground back ever'the `release trunk 133 -and also" opens tliecircuit vertical magnet (35. 'sidesniteh'wipeif- '1411"V and private magnet relay 71` to batteryj The vertical magnet operates in response .tothese iiiipulsestoraise the shaft Tand wipers (i7, GH and (39 two steps to a pointoppositethe .second ro'w'or level `of hauk contacts. The private magnet relay T1 operates. as iii the case ot' the selectors D and lL-to'elose' tile circuit of the private magnet 72. while the vertical magnet is operating. ft'elr the last;

impulse is delivered to the vertical inagnet from,gi-mind.(112 through 'lower windingpf' the relay 71 breaks Athecirciiit .of p iinite magnetfl7 which in turn deuergizes a-nd permits the side switch to pass to second po sitiori- The subscriber iio\\'.operat es the .calling devicefoi' the last d 'ngit-(l. llhe' relay (34 deincrgizes ten tiii'ies and'colnpletestlte circuit through tl'ie rotary magnet 66,.' This cireuit extends from 'ground A14(1"1 .thiit'iiugh ii-iagnet e'iiergizes teu' times to' rotate the l shaft-vipera onto-the contacts ot the ealled the -circuit ot'l th. private magnet T3. `fl`he,"

wipe'rstopass to third position. The. wiper 74. in passing to third positionyshifts--the,

holding ground forthe relay '11.5 -of selector gi'fqund onto the private ban'k contact-of ,the l called line in the. banks ofiall-'of flieen-Q .nectois that-have-acess to th'elines of' the'. 'calledsubseribe'r. This'eircuit extends from ground G"' throughjsile Aswitch-- wiper 77,

sofi

lines fsl'ibstation' A2, and' to 4evteiid vthe. con-1 ,i d uctor 1 51 toV the `l ine vconductor .1.64 through' springsfl' and '148.

f thirdjpositionfeoniplete theconjnectio frour the cal l-injglsubstationl .y A A tti-the substation teryfi's shifted front the Vrotary inlagnetto. fthe-ringer relay 78. 1 Tlie'mngerrelay now7 'eneigi'zes -o-ver .a circuit extending *front 'niittent'ly energizes through the medium of the interrupter 155'.tti-. p'lace'ringing4 eur- Y flireiitnon. Itiles-line of 'substation ..f\2.- This ringi'iig'z;l current-flows over a ciroiiiteXtend-- ing from one side if'generator R- through .springs 15S-"and 159,' wipers 7G and 67, springs 15:!andl'lifl'ine 164, bells 1135, 'conand' asz-sornast ie ringing relay again de-4 energizes alcircuitis"`oinple. ted extendingr` and 69, line 169, vSprings 1654 and 170,

. thence through the impulse springs receiver.

and 'transmitter 'at the sulistation A?. 'lniek. -"overlifne 1114. springs ll'aiid 152, wipers 6 7 andi-76, springs 15Qfand' 1GO and upper winding ot reilly 7'!) to liattery. This ci'r-- cuit. supplies the called subscriber witlitalkingfhattery'current,. ."The relay 79, upon eiieij'gi/L'ng, opeiis.the ringer -rel-ay circuit`lsubscriber receives his talking battery cur rent through the relay G4. The subscribers may now carry on a conversation.

ll`hc release of the apparatus used in the connect-ion is brought about by the replacing of the, receiver on the hook at the calling substation. The hanging up of the receiver at this substation opens the circuit of the relay (S1 of the connector I at the springs 83 and 8l, whereupon the relay 61 l'alls back and, by so doing, opens the circuit ot' the release relays 72, 115 and-'49 of the connector 1 and the selectors H and D, respectively. The relay 72, upon falling back, closes a circuit through the release magnet 70 of the connector. This circuit extends from ground G10 through the springs 131 and 13G, springs 137 and 170, magnet 70 and ott' normaLsprings 172 and 1,71 to battery. The switch is thereby released Aand the shaft, upon reaching its lowest position, separates the springs 171 and 172 to break the release magnet circuit. The relays- 115 and 49, upon fallin back,

close'circuits through thelr'respectlve release magnets similar to the one tracedrfor the connector. Vhen the relay 49 denergizes it also opens the holding circuit of the winding 17 of the line switch C. The winding 17 denergizes and allows the lunger to return to normal position. 'T ius the switches are all put in readiness for another call. i

lf the called line had been busy the private magnet 73 of the connector would not have deiinergized when the'relay 71 dcencrgized after the last digit. tt'as called, but would have remained energized over a cirenit, extending from theUground' .which would have bcen on the private bank contact ot' the busy line,` through the private wiper (i8, springs 143 and 142, lower winding of relay 75), ringer springs 1133 and 162, wiper T5 (in second position), springs 173 and 174 and private magnet 73 to battery. AsA the relay 71 deiinergizes, the spring 171 engages spring 173 before it disengagcs spring 17H, so that the relay 73 remains energized al'ter relay T1 denergizes, and at thel same time relay 79 is energized. 'lhc simultaneous energlzatimi of relay 7S) and private magnet 73 closes a circuit through the relay 8() extending from ground G through springs 176 and 175, springs 177 and 178, relay 8() and springs 179and 180 to battery, The relay 80, upon energizing, opens the operating circuit of the rotary magnet, shifts the holding ground for the relay 79 and magnet 73 from the. ground at the. private bank contact to ground (im, and also puts a busy signal on the line of the calling subscriber. This busy signal circuit extends from battery throt'tgh the-secondary o-l the induction coi] 181, through springs 182 and 183, wiper 76, l,ringer springs 160 and 161, condenser 153, thence over the circuit previously traced, through substation A, and back through the lower winding' of relay 61 toground,- thence through battery to`the starting point. The calling sub- 70 lscriber, upon hearing the busy signal, replaces the receiver on the hook. The act of replacing. the receiver on the hook releases the switches in the manner hereinabove described. The foregoing is a description of how one subscriber can call another subscriber on a different; line. In this description it will be remembered that the calling line is provided with a guarding pgtential at its 80 connector private bank contacts as soon as the line switch C operates. If now a party line subscriber should, attempt to call some other subscriber on his'own line through the selectors@ and H and connector .1, the S5 guarding potential at the connector private bank contacts would prevent the connector from completin the connection. Therefore have provide :the operators trunk vcircuit F, by means of which an operator may project ringing current back over a calling .party line to' signal any desired substation thereon. When a party linesubscriber wishes to communicate with Some other subscriber on his own line, he removes his re- 9o ceiverand operates his calling device for the digit corresponding-to the bank level of the selector D to which the trunks F are connected. 'Since in this instance the trunks I" are assumed 'to be connected with the 100 tenth or 0 level of the selectors, the calling subscriber operates his calling device for the digit 0. The selector D operates in response to fhe impulses for thisdigit in the saine mannerras explained for the first digit of the-nun ber 2220, except that its wipers are raised ten steps instead of two. Thus the wipers are raised ten steps and then automatically rotated onto an idle trunk F leading vto the manual board. As soon as the wipers of theselector pass to the third position a circuit is closed, through the doublewound relay 60. This circuit extends from `groundli0 through the -lower winding of relay t3() to the heavy conductor. thence over 115 the heavy conductors, as previously traced, to and through substation A, back over the. heavy Conductors and through the upper winding of relay 60 to battery. The relay (i0 pulls up and extends a holding and 120 guarding groundback over the release trunk` from ground G,tlixoi1gl1 springs 184 and 185. 1t also closes a circuit through the supervisory lamp 6l. This circuit extends from ground G18 through springs 186 and 125 187. springs 188 and 189 and lamp 61 to battery. The lamp is lighted and signifies to the. operator that she, is wanted. The operator. upon observing the signal, closes the key K, whereby the talking set' S 4is con- 130 nectml tojtl'iolin and a circuitI isals'o closed opnitorfs ringing'key ifu'oi'lianlsiu, nican i`n i through tho relay (3. This irciiibrxteiiils- .chillin-g' 'an autoniat'i switchfoi-"Cofincfing sirvil' "tlw.opratorroqizivstsh calling-Sulv iiicliuling 'aswitch individual if( 11 -i'inSwem jfhe operator..again-opnsitli hay -signalA Sly. thorv'liy"discoiiii'octing 'licr sot (L and (-losp tliv'cirruiL of. lamp :G2 ad'aho party-lino,"for releasing'safiil pubs .a 'non'. .ih oliling' ground unto. theA rolvasi-g moans controlled by fsaid; operato .tru-iik; hl-his circuit extends from ground nib'urfor pre-venting'sailirleas .1'. du' Y.the usiamo. linie;l

*ion 'saixl 70 ich, and-V nim-ha;A

line.' ftei:;lho hay Ii ils restored other on ihr san'iilino. Ti ifi-quiirs lliv lsorrtalkin;r 'ri'ii'rvntroniivrtvd `in' liiidgcjrofjli' partv-linv with said apparat-us'-wlion, om' 'only when ono paijfy calla -anolhviilinflic,

i 4-1' art \f'callsraiiotlrrr on tho' sa'uio liuc. ii'iuans sanno lino. aluiaiiual board for saldi-inging normally operativ(- lio rolraau said i-switrlr apparatus, ani-lfa common souic'ofopcrat- 1425 2. ln'a tcloliliouv,sjvstcln, a party-linr anA oprator ringing vlinv .inrcliani'sin, means ,130'

` called, a signal to indicate that a disconnection'lis desired, a manual board for said ringlng lkey, and a common source of op- -".erating and .talkinor current connected in Vbridge of the line by the establishment ot' connection to said board.

9.1111 a telephone system, a party-line, an operators selective ringing key apparatus, means including a'switch controlled by the calling subscriber for connecting the partyline with said apparatus only when one party calls another on the same line, andl means a't each station on said line" for controlling. the two sides of the latter in series to effect connection to the location of the? ringing key apparatusJ l0. In a telephone system, a party-line, an operators ringing key 'mechanism, means including an automatic switch for connecting said party-line with said mechanism only when one party calls another on the same line, and means at each station' on said line for controlling the two sides of the latter in series to eti-ect connection to the location of the ringing key. f

11. In a telephone system, a party-line, a selective ringing key apparatus, a trunk leading to said apparatus, a selector in which said trunk has a bank terminal, means for connecting said party-line with said selector, means for controlling said selector to connect the party-line with said trunk only when one party calls another on the same line,I and means at-each station on said liuc for controlling the two .sides of the latter in seriesv to efectf connection to the location of the ringing key.

12. In a telephone system, a party-line, an operators ringing key mechanism, means including an automatic switch for connectin said line with said mechanism only w en one party calls another on the same line, a signal responsive when the operator is called, a signal to indicate that a disconnection is desired, and means at each station on said line for controlling the two sides of' the latter in series to effect connection to the location of'the ringing key.

13.` In a telephone system, a party-line, an operators selective ringing key apparatus, and means including a switch controlled by the calling subscriber for connecting the party-line with said apparatus when one party' calls another on the same line, said party-line being provided with a non-numerical trunking switch individual thereto for extendinglr the initial connection therefrom, responsive tothe calling subscriber.

14. In a telephone system, a party-line, an operators ringing key mechanism. and means including an automatic switch for connecting said party-line with said mechanism when one party calls another on the same line, said party-line being provided witha non-numerical trunking switch individual thereto for extending the initial connection therefrom` responsive to the calling subscriber.

15. In a telephone system, an operator-s ringing key mechanism, a party-line, and means comprising a rst selector for eonnecting the party-line with said mechanism when one party calls another on the same line, said party-line being provided with a non-numerical trunking switch for extending the initial connection therefrom. responsive to the calling subscriber, a plurality of magnets for controlling said switches, and means controlled -by said 'mechanism for signaling a subscriber on said party line over a path excluding all of said magnets.

16.- In a. telephone system, a party-line, a selective-ringing key apparatus. a trunk leading to said apparatus, a selector in which said trunk has a bank terminal,`a nonnumerical trunking switch responsive to the calling subscriber for connecting said partyline with said selector, and means for controllingsaid selector to connect the partyline with said trunk-when one party calls another on the same line, a plurality of magnets for controlling said switches, and means controlled by said mechanism for signaling a subscriber on said party line over a path excluding all of -said magnets.

17.- In a telephone systeni, a party-line, an operators ringing key mechanism, means including an automatic switch for onnecting said line with said mechanism when one party ealll; another on the same line, a signal responsive when the operator is called,

and'a signal to indicate'that a disconnection is desired, said party-line being provided with a non-numerical trunking switch individual thereto for extending the initial con-4 nection therefrom, responsive to the calling subscriber.

18. In a telephone system, a party-line, an automatic switch. an operators ringing key mechanism, trunk lines extending'to said mechanism, means for controlling said switch for .selecting one of said trunks, means controlled by said ringing key mechanism for supplying. ringing current back over said selected trunk line to said partyline, means controlled b y a subscriber on said party-line for releasing said switch, and means controlled by said operators mechanism for preventing said release.

19. In a telephone system, a party-line,an automatic switch having a plurality of contact levels, an opcrators key mechanism, trunk lines extending to said mechanism fromone or more of said contact levels, means for controlling said switch to select one of said trunks,'means controlled by said .55 occupied, means for releasing said automatic ringing key mechanism Afor supplying ringing current back .over said selectedtrunk line to said party-lille. means normally 0perative. to release said switch when the silbscriber replaces his receiver on the hook, and

means for preventing this release lwhcna party establishes connection with said selective ringing key apparatus. I

:20. In a telephone system, a party-line, an automatic switch, an opcrators ringing key' mechanism, trunk lines extending to said mechanism, means for controlling said ,switch over two sides of thc line circuit in series for selecting one of said trunks, mag- `nets for controlling said switch, and means controlled by said ringing key mechanism for supplying ringing current back over said selected trunk line'to said party-line over a path excluding all of said magnets.

21. In a telephone system, a party-line, an

automatic switch having a ,phn'ality of contact levels, an operators key mechanism,V

ringing key mechanism for supplying ringing current .hack over. said selected trunk line to said party-line, a signalat. said operators position for indicating when an operator is called, a second signal for indicating when a trunk is occupied, means for re leasing said automatic switch, and means controlled by said operator for preventing said release.

25. In a telephone system, a party-line, an automatic switch, an operator-s ringing key mechanism, trunk lines extending to said mechanism, means for controlling said switch over two sides of the line circuit in series for selecting one of said trunks, means controlled ing ringing current'back over said selected.

Vtrun'k line to said party-line, a signal at said by said ringing key mechanism for supply..A

26. In a telephone system, a party-line, an

automatic switch having a'plurality Ofcom-- '-tact levels, an operators key mechanism,

ing-current hack over said selected trunk line to said party-line.

22. In a telephone systempa, party-line, an

operators ringing key mechanism, means including an automatic switch for connecting` said line, with said mechanism when one party calls another on the same-line, asignal, means for operating said signal when aii'operator is called, means for rendering'said signal inoperative when Vsaid operator answers, a second signal operated therca fter dui'iiig the connection, means for releasing said automatic switch, and means controlled by said operator for preventing said release.

23. In al telephone system, a party-line, an auton'iat-ie switch, an operators ringing key mechanism, trunk lines'extending -to said mechanism", means for controlling lsaid switch for selecting one of said trunks, means controlled by said ringing key mechanism for supplying ringing current -back over said selected trunk line to said party line, a signal at said operator-s position for indicating when an operator is called, a second'signal for indicating when a trunk is trunk lines extending to said' mechanism from one or more of said Acontact levels,

means for controlling said switch over two sides of the line circuit in series to first select one of said levels and to thereafter select one of said trunks, means controlled by said ringing key mechanism for supplying ringing current back over said selected trunk line to said party-line, asignal at said operato1"s-position for indicating when an operator is called, and a second signal for indicating when the trunk is occupied.

27.M Inea telephone system, a part-y line, a ring-back apparatus' for enabling one party to call another on the same line, means including a first selector having -vertical and rotary motion for connecting the line with the said apparatus, and means for supplying'currents of different, frequencies, said ring-back apparatus provided "with means controlled Aby an operator .for selecting the l proper current for signaling a" party on said ine.

28'., In a telephone system, a partly line, a

currents of difei'ent"f1'equencies, a rst selector for extending'connection to said apparatus, means for extending connection from said line to said first selector, a plurality of magnets for controlling the extension of said connection, said ring-back apparatns'provided with means controlled by an operator for selecting the proper frequency fo'rsignaling substations on said line, and for applying said signaling current tol said line over apath excluding all vofsaid magnets. L

.29. In a telephone system, a party line,

' with a source of .ringing current to opmeans t'or automatically extending connection trom said line including a'ring-back apparatiisl'orliiiabling one partyy to callanother on the saine liuc, means t'or connecting thc l-ine with the said apparatus, a plurality ot` magnets for controlling said connecting means. and means for supplying dittercnt. kinds ot'v ringiinc` current, said ring-back apparatus provided with means,controlled by aq"opcrator Jfor selcctiiigthe proper current for signaling a party on said line. and toiapplying said signaling current to said liiic over a patti excluding all of said magnets.

*30. In a telephone system, a plurality of -party lines and trunk lines divided into groups, a ring-back apparatus t'or enabling oneV party to call another on the saine line, a tirst, selector haring motion in one plane to select groups ot' trunks and i'notion in an intersecting plane to'flnd -a trunk in a selected group for connecting the line with the said apparatus, and means for supplying currents of different. frequencies, said ringback apparatus vprovided witlr-iiieans controlled by an operator tor selecting the proper frequency for signaling a party on said line. 31. .In a telephone system, a line, a substat-io'n and a-s'ignal in bridge ofsaid line, ay trunk line extending to'an operatowsposif4 tion, means including, an automat-ic switchcontrollable by the subscriber a't said stat-miie. for connecting with said trunk line. a'. Vring'- ing key apparatus for connecting said trunk.'-

crzite said signal, means normally 'operati-ve to\release said switch when the subscriber replaces his receiver'on the liook, and means whereby thc operator can prevent such :rclease after connection has been established with said trunk line i 32. In a telephone system. a party line and i a plurality of subscril'icrs stations in bridge thereof. a trunk( line extending to4 an operators position, means including an'au'toniatic switch controlled by a calling subscriberl'on said party line for connecting -wit-h' szfid trunk line. ringing equipment' associated said trunk line for yselecti rel y signalingsiilistations on said party line, means-normally' operative to release said switch When the subscriber replaces his receiver. on the hook-` and means whereby the operator can prevent such release after connection 'has established withsaid trunk li-ne. 1 l In' a' telephonejsystem, 'aplin'alityof party lines, a 4plurality ot subscribers stations, in bridge vof each line, a trunk-lino extending to an operators position. automatic switches accessible `to calling lines; each `soi'itch when 'seized b v al calling line cont-roh lable over tliejtwosides of such calling line in seiiesffor connect-ing with sai-d trunk line.

ringii'ig equipment associated with said trunk' line for selectirelr.' signaling subsi-ations on said party line. means noriiiallr operative to release a seized switch whcirtlic subscriber replaces his i'eceirci'on the hook. and means whereby the operator can prcrent such release after' connection has` been established with said trunk line.

34. In a telephone system. a line. a substation anda signal iii bridge ot' said line. a trunk line extendingl to aii operators position. means including an automatic switch controllable by the subscriber at said stilistation for connecting with said trunk line. a ringing key apparatus t`or connecting said trunk with a source of ringing current toopcrate said signal, a common source'ot operating zu d talking currentl connected in bridge ofsai( trunk line. and siibscribhei controlled means for releasing said-connection.

35,'In a telephone system. a party line and aplurality of subscribers stations in )ridge thereof. a trunk "line extending to an operatofs position. means including an autoiiiatic switch liav'inguvertical and rotary motion` controlled by a'fcalling subscriber on said party line for connecting with saidti'iuik.liiie. ringing equipment' associated with said trunk line tor selectively .signalingfsubstations on said 'party line, and a c oinuion source of operating `and talkine'I .current connected in bridge of said trunk 36. In .a telephone system, apluralityof party lines, a plurality ot subscribers` sta# tions in lbridge of each line7 a trunk line eX- tending to an operators position, automatic "switches, means for connecting one, of said :p art'y' lines with any one of' said switches, .each switch when seized by a calling line controllable overthe two sides of such cal1 ing 'line in series for connecting`v-jith"'said 'trunk line, ringing' equipmentassociated with said trunk line for selectively. .signaling s ubstations on said party line, and faconr mon source of operatingand talking cur.- rent connected in'bridge olf said trunk line.

'37. In a telephone system. a line. a sabstation and a signal in bridge. of said line. a trim-lc' line extending .to an operato.1"s posil tion, ineansincluding an automatic switch controllable by the subscriber at said stilista tion for connecting `with said trunk line, a ringing key apparatus fol' connecting said `trunk with a source`of ringing current to operate said signal, a signal toindicateto the operator when a call is received relayf t'or controlling said signal connected in .se-

ries with'a lbattery across the talking loon-- 'diictors of sairltnunk Iline, sa'id relay also controlled by saidcalling subscriber. for rer bridge thereof, a. trunk line extending to an operators position, means including an automatic switch controlled by a calling subscriber on.said.party line for connecting party lines, a plurality of subscribers stations in bridge of each line, a trunk lineex;

tending to an operators position, ailtoiiiaticr switches, means for connecting any one of said party lines lwith any zonefof said switches, each switch when seized by a lcalling line. controllable 'over the two sides of such calling line in seriesrfor connecting with said trunk line, ringing equipment as-' sociated with said trlink line for selectively signaling substations on said party line, a signal individual to the/operator when a. call is received, and a common source o foperating and talking current connected in bridge of said trunk line.

40. In a telephone system, a line, a sub1` station and a signal in bridge of said line.

a'trunk line extending to an operators position, means including an automatic-switch controllable by the subscriber at said sillistation for connecting with said trunk line, a ringing key apparatus for connecting said trunk with Aa source of ringing current to operate said signal, a signal to indicate to the operator when a call is received, a signalto indicate to the operator that theI trunk is occupied, and a common source of operating and talking current connected in bridge of said trunk line.' y

41. In a telephone s vstein, a party line and a Aplurality of subscribers stations in bridge thereof, a-trunk line extending to :in operators position, me'ans including an antomatic switch controlled by a calling subscriber on said party line for 'connecting withfsaid .trunk line, ringing equipment associatedwith said A,trunk line for selectively signaling substations onsaid party line, a.

signal to indicate to the operator when a call is received, a signal to indicate to the oper( tor tliattlie trunk is occupied, and a. common Source of operating and talking urrent connected in bridge'of said trunk line.

42. In a telephone system, a plurality of partylnes, a pluralityf subscribers stationsin bridge of each line, a trunk line eX- tending 'to' an operators position, automatic switches, means for connecting any one 'of said party lines with any one of said switches. each switch when seized by a calling line controllable oveLi/thqtwo sides of such calling line in series for connecting with` said trunk linc, ringing equipment associated with" Psaid ti'uiik line for selectively signalingsubstations o`n said party line, a signal to indicate t0 the operator when acall is received, a signal to indicate to the operator that the trunk is occupied,` and common source of operating and -talking current'connected in bridge of said trunk line. g

43. In a telephone system, a party line and a plurality of substatons in. bridge thereof, a'trunk line extending to an operator`s position` means including a non-iininerical switch responsive to the removal of` the receiver at one of said substations and da directiv'el y controlled numerical switch accessible thereto for .connecting said party line witli'sa'idtrunk line. sources of ringing ,current of different character, and means for separately connecting said sources with part)v line selectively.

HI In a telephone system, a party line and a pluralityof snbstations in'bridge tliereof,'a trunk line extending toan operators position, nieansincluding' a non-ini- `inerickalv switch responsive to theremoval of the receiver at one'of said, substations and a` dircctively. controlled numerical switch accessible thereto for` connect-ing said .pai-tgv line witli'saidtrunk line, sources of ringing curreiit of different character, means for separately connecting said sources with said trunk lineito signal substations on said party lin'e selectively, means normally operative to release said switches w-lien the subscriber replaces his receiverf'on tlie'hook, andjncansvhereby the operator ca'n prevent such release iifter connection has been established with said trunk linerJ 45. In a telephone system, ,a party line and a plurality fot' substationsein ridge thereof,l a trunk line extending toan operators position, means including a non-numeri 'al switch. responsive .t0 the removal 'of the receiver at oneyof said Substations fand a directively controlled numerical switch accessible thereto for connecting said part-y line with said trunk line,-sources ofl source of operating and talking current con# nected in bridge ofsaid trunk line.

said trunk line-to signal substations on said 46. In a telephone system, a party line and a plurality of s'bstations in. bridge thereof, a trunk line extending to an operators ositionf'means including a nonlnumerical) switch responsive' to the removal of the receiver atione of said substations and a idirectively' controlled numerical y connected in bridge of said trunk linc` and f connected thereto.

a signal to indicate to thc operator that' the trunk is m'cnpicd.

47. In an automatic telephonesystem, a plurality of party lines, a plurality if-numerical selectors-'and conncctois for connecting a calling subscriber on one line with a called .subscriber on another liuc, a trunk line cxtending'to au operatoi"s position accessible to certain of said selectors whereby calling subscribers may connect withA an operator, a source of talking current'iii bridge,

ofvsaid trunk'line, and i'ingiiiggjfifquipinent,

assiwiated 'with said trunk for projecting ringing currentAV back over.

48. an automatic telephone'sjstein,..lii. plnrality'o party lines, a plurality; of 'nu'j nierical selectors and`co'nncctors 'for coin'iccting a calling'x snbscriberjon' one line with. a called,` subscriber on another linc,4a trunk line extendingtol an Aoperations'gposition, means for nialingsaidtruiik line accessible to certain oie-said selectorswhereby calling subscribers-may connect Awith an operator. a. source of talking 'current bridge of said trunk line, and fa' selective i'iiiging equipment..associated with said trunlt for projecting ringing ci'iirrent of different frquencies' back over acalling line connected thereto.

49. In anautoniatio telephone system` a. plurality of party lines," a 'plurality ,olf numerical selectors and'coiiiicctors for con'- neeting acallin subscriber on one line withV a called subscri on anothei-linc` a trunlr line extendin t,o 'an' operator`s position, means for ma ing said trunk line,.'ac a\ssili`lc to certain' of said selectors whereby calling.

subscribers may connect with. an opratoig-ai source of talking current` in bridge-of said trunk line, anda manually operated mechal nisim associated with said"trii'nlgxwhereby 'the operator is enabled to project ringingcurrent back-over a eallinfr line' atthe 'request. of the 'calling subscri lrj 50. Ina telephone system, 'e party line.' `and a plnrality of substations in bridge' thereof, a plurality of trunk lines at the, exchange,` extending to an opcratorsj positionA and a plurality ofr-runk lines at tlien exchange extending to automatic switches,-

Aa selector switch, means for making 'said selector switcliaccessible to said'partyline,A said selector'switeh controllable from a' substation tliereonior connecting with. aniv one .on any-,line connected thereto. a' *calling line the operator fo1' ringing back over any trunk lineof the first kind when said party line is connected thereto to signal one of said substations.

. l51'. In a telephone system, a plurality of lines, a plurality 0f substations in bridge. of cach liuc, a plurality of trunk lines at the exchange extending Ato an opcrator`s position and a plurality of trunk lines at the exchange extendingr to automatic switches foipusc in interconnecting said lines, a selector switch, means foi"iiial\'iiig said selector' switch accessible to a calling one ot' said -llncs and I controllable vfrom a substationthereon for connecting with any one of said trunk-lines ot' either kind. and a selective. ringingeqnipmcnt,controlled b v the operas.

tor for ringing back 'over any trunk line .of the first kind 'to signal a called substation 52. yflu-a telephone system. a partv lincua st lcctiijeI ringing key appai'a'i'tus. a trunk lin'o' leading' to, said apparatus, a switch con- "ti'iilled by a subscriber on said party line for connecting said party linewith said trunk,- line. a. conductor extending through "said switch to said apparatus. a subscriber 4` controlled means for o peningsaid conductor to release said switc i.

53, ln a telephone s ifste'ii. a partylineian operatoi"s position` a'trunk line leading to said 'opcratofs po tion.'selccti\e signals ing apparatus"associated with sa-iittrunk l`ii'ic,' aprogressively A movable switch having -wipers to said 'switch for extending a Vconnection froml said, party line to'said trunk line. over said wipers to enable one snliscribcr to call another oii the saine line., a circuit' common to said switch and tinnk line passing through onel of said wipers; and means 'controlled by 'the opci'ator'for 'opere ing said circuit to release said switch.

54.111 -a telephone-system, a party line, 'a' select-ive' ringiiig'- lkey, apparatus, a trunk- 4line leading to said`apparatus,'a selecton having wipers Aand 'a .liarik, terminals for said trunk vline 1n' said bank, 'means 'for operating said switch to more said wipers o connect ivith said terminals, tofenablefone party to call another on the same` line, a1

circuit,"closed. by the connection of said". wiperivith said bank. and niean's' controlled by' the calling snbscribci" for opening said- -circiiit -to 4release said switch.

55.A In a telephoner'system," a 'party line` a selective ringing key apparatus, ls i'tri'ink linev leading -to said apparatus', means for connecting said party line-:with said trunk line, t0 enable. one parti'y torall another on the same line, said means 'inc-hiding a switch individual'to said party-liuc. and subscriber controlled means 'for releasing sai-d connection, und means for preventing the subparty to cull another on the sume lino, und 10 scriber from releasing said connection. means controlled by the subscriber for re- 56; In g1 telephone system, a plurality of leasing said numerical selector.

' party lines,4 :L selective ringing key uppa- Signed by me at Chicago; Cook'county,v ratus, a plurality 0f trunk lines leading to A Illinois, this Q9 day 0f Ju'ne, 19l0. i

said apparatus, a numerieal selector switch 'TALBOT G. MAR'IIll.l

, common to said party lines'for extending a, Witnesses:r

connection from one of said party lines to ARTHUR J. RAY, anyone of sa1d trunkllnes to enable one EDWARD D."FALES. 

